为什么 RecyclerView item 只在点击两次后才改变背景颜色？

Question

我一直在探索 Recyclerview 和 Cardview，我偶然发现了一个我不知道如何处理的问题。我的 recyclerview 工作正常，但是当我让 recyclerview 的项目背景在点击时改变颜色时，它表现得很奇怪。

好的，recyclerview 正常加载，但是当我第一次单击某个项目时，该项目的背景颜色闪烁其新颜色，但随后保持其默认颜色。当我第二次单击任何项目时，recyclerview 的项目才会更改其背景颜色，因为它应该与单击的项目的其余部分一起更改。

从我添加到代码中的 Log.d 中，我发现第一次点击与第二次（以及其余）点击的不同之处在于 public PremiseAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) class PremiseAdapter。我发现与我的问题类似，但我认为我的代码不是这样工作的。

日志如下。

加载 recyclerview 及其 Cardview 项目

.... D/rcvTest: PremiseAdapter.PremiseAdapter
.... D/rcvTest: PremiseAdapter.getItemCount
.... D/rcvTest: PremiseAdapter.getItemCount
.... D/rcvTest: ---------------------> PremiseAdapter.ViewHolder.onCreateViewHolder
.... D/rcvTest: [ViewHolder].ViewHolder.TOP
.... D/rcvTest: PremiseAdapter.onBindViewHolder
.... D/rcvTest: [ViewHolder].bindTo.TOP: FroyYo Mart
.... D/rcvTest: [ViewHolder].bindTo.BOTTOM FroyYo Mart
.... D/rcvTest: PremiseAdapter.onBindViewHolder.get(position)
.... D/rcvTest: PremiseAdapter.getItemCount
.... D/rcvTest: ---------------------> PremiseAdapter.ViewHolder.onCreateViewHolder
.... D/rcvTest: [ViewHolder].ViewHolder.TOP
.... D/rcvTest: PremiseAdapter.onBindViewHolder
.... D/rcvTest: [ViewHolder].bindTo.TOP: Ice Cream Store
.... D/rcvTest: [ViewHolder].bindTo.BOTTOM Ice Cream Store
.... D/rcvTest: PremiseAdapter.onBindViewHolder.get(position)

首先点击项目

.... D/rcvTest: [ViewHolder].ViewHolder.listener: null
.... D/rcvTest: [ViewHolder].ViewHolder.getAdapterPosition(): 1
.... D/rcvTest: [ViewHolder].ViewHolder.position: 1
.... D/rcvTest: getLayoutPosition(): 1
.... D/rcvTest: [ViewHolder].ViewHolder.position != RecyclerView.NO_POSITION
.... D/rcvTest: PremiseAdapter.getItemCount
.... D/rcvTest: PremiseAdapter.getItemCount
.... D/rcvTest: ---------------------> PremiseAdapter.ViewHolder.onCreateViewHolder
.... D/rcvTest: [ViewHolder].ViewHolder.TOP
.... D/rcvTest: PremiseAdapter.onBindViewHolder
.... D/rcvTest: [ViewHolder].bindTo.TOP: Ice Cream Store
.... D/rcvTest: [ViewHolder].bindTo.BOTTOM Ice Cream Store
.... D/rcvTest: PremiseAdapter.onBindViewHolder.get(position)

第二次（以及其余）点击该项目

.... D/rcvTest: [ViewHolder].ViewHolder.listener: null
.... D/rcvTest: [ViewHolder].ViewHolder.getAdapterPosition(): 0
.... D/rcvTest: [ViewHolder].ViewHolder.position: 0
.... D/rcvTest: getLayoutPosition(): 0
.... D/rcvTest: [ViewHolder].ViewHolder.position != RecyclerView.NO_POSITION
.... D/rcvTest: PremiseAdapter.getItemCount
.... D/rcvTest: PremiseAdapter.getItemCount
.... D/rcvTest: PremiseAdapter.onBindViewHolder
.... D/rcvTest: [ViewHolder].bindTo.TOP: FroyYo Mart
.... D/rcvTest: [ViewHolder].bindTo.BOTTOM FroyYo Mart
.... D/rcvTest: PremiseAdapter.onBindViewHolder.get(position)
.... D/rcvTest: PremiseAdapter.getItemCount

这是我的 PremiseAdapter.java 文件，其中包含我的 PremiseAdapter class 和 ViewHolderclass.

public class PremiseAdapter extends RecyclerView.Adapter<PremiseAdapter.ViewHolder> {

    private ArrayList<Premise> mPremiseData;
    private Context context;
    private int selected_position = -1;
    OnItemClickListener onItemClickListener;

    public interface OnItemClickListener {
        void onItemClick(int position);
    }

    public void setOnItemClickListener(OnItemClickListener itemClickListener) {
        onItemClickListener = itemClickListener;
    }

    public PremiseAdapter(Context context, ArrayList<Premise> mPremiseData) {
        Log.d("rcvTest", "PremiseAdapter.PremiseAdapter");
        this.mPremiseData = mPremiseData;
        this.context = context;
    }

    //Required method for creating the viewholder objects.
    @NonNull
    @Override
    public PremiseAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        Log.d("rcvTest", "---------------------> PremiseAdapter.ViewHolder.onCreateViewHolder");
        return new ViewHolder(LayoutInflater.from(context).inflate(R.layout.list_premises, parent, false), onItemClickListener);
    }

    //Required method that binds the data to the viewholder.
    @Override
    public void onBindViewHolder(@NonNull PremiseAdapter.ViewHolder holder, int position) {
        // Get current premise.

        // Populate the textviews with data.
    }

    @Override
    public int getItemCount() {
        Log.d("rcvTest", "PremiseAdapter.getItemCount");
        return mPremiseData.size();
    }


    /*----------------------------------- CLASS VIEWHOLDER -------------------------------------------*/
    /*----------------------------------- CLASS VIEWHOLDER -------------------------------------------*/

    /*class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {*/
    class ViewHolder extends RecyclerView.ViewHolder {
        // Member Variables for the TextViews

        //Constructor for the ViewHolder, used in onCreateViewHolder().
        ViewHolder(@NonNull View itemView, OnItemClickListener listener) {
            super(itemView);
            cardView = itemView.findViewById(R.id.cardview_premise);

            Log.d("rcvTest", "[ViewHolder].ViewHolder.TOP");
            // Initialize the views.

            // Set the OnClickListener to the entire view.
            int clickedColor = Color.parseColor("#D5F5E3");

            itemView.setOnClickListener((v) -> {
                int position = getAdapterPosition();
                Log.d("rcvTest", "[ViewHolder].ViewHolder.listener: " + listener);
                Log.d("rcvTest", "[ViewHolder].ViewHolder.getAdapterPosition(): " + getAdapterPosition());
                Log.d("rcvTest", "[ViewHolder].ViewHolder.position: " + position);
                Log.d("rcvTest", "getLayoutPosition(): " + getLayoutPosition());

                if (position != RecyclerView.NO_POSITION) {
                    Log.d("rcvTest", "[ViewHolder].ViewHolder.position != RecyclerView.NO_POSITION");
                    itemView.setBackgroundColor(clickedColor);
                } else if (position == RecyclerView.NO_POSITION) {
                    Log.d("rcvTest", "[ViewHolder].ViewHolder.position == RecyclerView.NO_POSITION");
                    itemView.setBackgroundColor(clickedColor);
                }
                notifyItemChanged(position);
                notifyItemChanged(getLayoutPosition());
            });
        }

        void bindTo(Premise currentPremise) {
            // Populate the textviews with data.
            Log.d("rcvTest", "[ViewHolder].bindTo.TOP: " + currentPremise.getPremiseName());
        }
    }
}

Answer 1

试试这个。最近我编写了这个并且它工作正常，希望它也能解决你的问题。

 int row_index = -1;
 holder.itemView.setOnClickListener(v -> {
            row_index = position;
            notifyDataSetChanged();
        });
        if (row_index == position) {
            holder.layout.setBackgroundColor(Color.parseColor("#ff6600"));
        } else {
            holder.layout.setBackgroundColor(Color.parseColor("#ffffff"));
        }

Answer 2

我通常在 onbindviewholder 中实现 onclick 侦听器，它们似乎工作正常。我建议你试试看。
将这段代码移动到onbindviewholder

           int clickedColor = Color.parseColor("#D5F5E3");
            /*itemView.setBackgroundColor(defaultColor);*/

            holder.itemView.setOnClickListener((v) -> {
                int position = getAdapterPosition();
                Log.d("rcvTest", "[ViewHolder].ViewHolder.listener: " + listener);
                Log.d("rcvTest", "[ViewHolder].ViewHolder.getAdapterPosition(): " + getAdapterPosition());
                Log.d("rcvTest", "[ViewHolder].ViewHolder.position: " + position);
                Log.d("rcvTest", "getLayoutPosition(): " + getLayoutPosition());

                if (position != RecyclerView.NO_POSITION) {
                    Log.d("rcvTest", "[ViewHolder].ViewHolder.position != RecyclerView.NO_POSITION");
                    /*listener.onItemClick(position);*/
                    itemView.setBackgroundColor(clickedColor);
                } else if (position == RecyclerView.NO_POSITION) {
                    Log.d("rcvTest", "[ViewHolder].ViewHolder.position == RecyclerView.NO_POSITION");

                    itemView.setBackgroundColor(clickedColor);
                }
                notifyItemChanged(position);
                position = getLayoutPosition();
                notifyItemChanged(position); //duplicate
            });

只要确保更改

itemView.setOnClickListener(...)   to   holder.itemView.setOnClickListener(...)

为什么 RecyclerView item 只在点击两次后才改变背景颜色？

Why does the RecyclerView item only change background color after clicking on it twice?

android

android-recyclerview

android-adapter

android-cardview

android-viewholder